The consumption of tobacco products will all its deletereous effects upon the general health of our populace, was and still is major health problem. Although the number of people consuming cigarettes has decreased over the last decade, smokers are using more cigarettes and adolescents are consuming not only cigarettes, but also large quantities of smokeless tobacco. There is also concern with regard to effects of passive smoke on non-smokers such as children and adolescents both in the workplace and in the home. Because of these problems, there is a considerable effort being put forth by the U.S. Government to obtain the goal of a smoke-free society which will require specific analytical procedures to monitor and evaluate the success of such efforts. A variety of methods are available for the specific and sensitive determination of nicotine and its major metabolite, cotinine, in biological fluids. Most of the available assays (i.e., HPLC, GC, RIA) require expensive equipment, trained personnel, and a laboratory setting. We propose to develop an enzyme immunoassay (EIA) which will be useful for the detection of various concentrations of cotinine in biological fluids. This assay can be adapted for use in monitoring the effects of tobacco products on child development and for epidemiological studies on smoking status in the populace. The assay is simple, fast (less than 5 minutes), noninstrumented, and thus, easily portable for use in the workplace or physicians' office.